The control of macromolecule synthesis will be studied. Specifically, two separate projects will be followed: 1) The mechanism through which host protein synthesis is stopped by virulent phage or phage ghost infection will be studied. Possibility that ghost infected cells can regain its full activity for functional protein synthesis by addition of cellular material will be explored. 2) Role of ribosome releasing factor for the synthesis of protein will be studied. We discovered a protein factor which catalyzes release of ribosomes at the end of cistron. We wish to establish the physiological role of this factor. We will show that for recycling of ribosomes this factor is indispensable. BIBLIOGRAPHIC REFERENCES: Kaji, A., Kaji, H. and Otaka, T. Inhibitors of protein biosynthesis. Handbook of Molecular Biology, CRC Press. 1976. Otaka, T. and Kaji, A. Mode of action of Bottromycin. J. Biol. Chem., 1976.